In the prior U.S. Pat. No. 4,403,692, of William F. Pollacco, issued Sept. 13, 1983, there are disclosed several utilitarian designs of motor oil change kit, especially adapted to be bought and used by "do-it-yourselfers", particularly, persons changing the engine crankcase oil of their own motor vehicle, or performing a like task for a friend, at a site removed from a gasoline station, commercial automotive repair facility or the like.
At any time when automotive engine oil is changed at a site which is not located right at a commercial facility that has a regular system for catching used oil and recycling it or disposing of it properly, there is all too high a likelihood that the used oil will be improperly disposed of at a place where it will contaminate the soil, the air, drinking water and/or the food chain on which we all depend.
Some potential do-it-yourself oil changers are reticent to undertake the task, or perform such maintenance all too infrequently, because of the potential messiness of catching the old oil, and of uncertainty in how to go about disposing of it properly and without spills.
Many of these problems are solved by use of the oil change kit and system which are described in the aforementioned U.S. patent of Pollacco.
For prototyping and further development a motor oil change kit according to the third embodiment, FIGS. 5-9 of the Pollacco patent was selected, with a plan to omit the disclosed drain pan cover in favor of the disclosed frangible wrapping band for initially keeping the kit parts assembled together. The prototype, as with the fourth embodiment, would use a standard new oil jug with a usual upwardly projecting neck having a screw cap. According to the preferred form of that embodiment as disclosed, the jug of new oil initially comes to the user nested in a drain pan. The user de-nests these kit parts, closes-off the bottom outlet of the drain pan, drains the old oil from the crank case into the drain pan, pours the new oil from the jug into the filler tube of the automotive engine, then supports the drain pan of old oil on the empty jug and then opens the bottom outlet of the drain pan allowing the old oil to drain into the jug, whereupon the jug of used oil could be recapped and taken to an oil recycling station and the empty, used drain pan turned-in at the same place, or discarded.
The means disclosed in the aforementioned U.S. patent of Pollacco for openably closing the bottom hole in the drain pan is a so-called Cap-n-Plug closure comprising an externally threaded plug secured on a rod headed by an internally threaded cap. The rod is disclosed to be sufficiently long, that when the plug is in place and oil is drained into the drain pan until the crankcase has been substantially drained, the cap remains high and dry above the surface of the old oil in the drain pan. Thus the user, after he or she has supported the drain pan of old oil on the empty jug can easily remove the plug by twisting the cap, and not get his or her hands dirtied. The cap portion of the closure could then be used to re-cap the jug, now full of old oil, for convenience in returning the old oil to an oil recycling station, or in otherwise properly disposing of the old oil.
Early in the commercial prototyping and developing process, it began to appear that the particular Cap-n-Plug closure means earlier chosen for temporarily stoppering the drain opening in the bottom of the catch pan for old oil would lead to undue complexity in the manufacturing process. Accordingly, although we remain utterly convinced of the soundness of the broader principles of the oil change kit and system as disclosed in the aforementioned U.S. Pat. No. 4,403,692, of Pollacco, we were so stimulated by the prospect of commercializing a convenient and environmentally sound means for enabling the do-it-yourselfer to change his or her motor vehicle engine oil, that we have proceeded to improve the used oil catch pan, the means for temporarily closing the drain opening of the used oil catch pan, and the way that the used oil catch pan may be supported on the emptied new oil jug, for draining the used oil into the jug.